Color changing paint and varnish remover

ABSTRACT

A color change paint and varnish removal formulation is provided. The formulation comprises: at least one penetrant, at least one water insoluble carrier and at least one color visible colorant whereby the formulation is applied to the target area and as the surface of the formulation dries, the penetrant migrates away from the dehydrating surface and a surface crust of beads is formed; the beads have a particle size that allows the scattering of visible light into white light and produces the whitening and dilution of the visible color and thus, there is a color change to indicate that the stripping action of the formulation has ceased and is ready for the scraping and removal step.

RELATED APPLICATION

This application is a continuation-in-part of U.S. application Ser. No.11/280,594, entitled “COLOR CHANGING PAINT AND VARNISH REMOVER”, whichwas filed on Nov. 17, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to a color change paint and varnishremover. More specifically, the present invention provides for a paintremoval formulation having a color change feature to indicate when thestripping action of the formulation has substantially ceased and isready for removal. The formulation comprises: at least one penetrant, atleast one carrier and at least one colorant whereby the formulation isapplied to the target area and as the surface of the formulation dries,the penetrant migrates away from the dehydrating surface and a surfacecrust of beads are formed; the beads have a particle size that allowsthe scattering of visible light into white light and produces thewhitening and dilution of the visible color. This color change indicatesthat the stripping action of the formulation has ceased and is ready forthe scraping and removal step.

2. Description of the Related Art

The term “paint and varnish remover” as used herein refers to chemicalcompositions which can strip or remove all types of coatings, such as,paints, lacquers, enamels, varnishes, shellac, polyurethane, epoxies,and other coatings used on substrates such as metal and wood.

Methylene chloride paint strippers have long been the standard forstripper performance. Although effective in stripping action, highvolatility shortens the working time for paint and varnish removal,often requiring more than one application when used on thickeraccumulations of paint. In addition, the environmental concerns and thepotential carcinogenic effects based on lab tests on mice and rats, haveled to ever increasing regulations concerning its use.

Other solvents, such as toluene, xylene, methanol, acetone, ethanol inaddition to being flammable, are themselves or in various combinationsalso highly volatile, requiring multiple applications when thickaccumulations of paint are to be removed, and therefore suffer becausetheir work life is insufficient to permit complete penetration of thepaint layers before drying out.

The use of safer solvents to replace methylene chloride and flammablepaint and varnish removers, are well documented in previous patents.N-methyl-2-pyrrolidone (NMP) has long been employed as the main activeingredient in various paint stripper compositions that offer saferalternatives to methylene chloride and flammable solvent compositions.(NMP) costs over four times as much as methylene chloride, and as muchas ten times as much as common flammable alternatives, and variousattempts have been made by adding less costly components to (NMP)mixtures, while still maintaining removal properties. U.S. Pat. Nos.4,120,180; 4,749,510; 5,006,279; and 5,015,410 all refer to variouscombinations of (NMP) and various aromatic hydrocarbons and otheradditives to maintain removal efficiency and lower overall costs.Unfortunately, such aromatic hydrocarbons are under increasingregulatory pressures as hazardous air pollutants, and their insolubilityin water makes them more difficult to remove from the surface by waterwashing. Furthermore, these aromatic (NMP) blends, using recommendedthickeners, primarily of the cellulosic type, suffer from poor sagresistance, especially when sheared by rapid brushing action orspraying. This leads to insufficient thickness of paint and varnishremover to penetrate effectively, before drying out. U.S. Pat. Nos.4,666,626 and 4,732,695 refer to paint and varnish removers based on oxyhexyl acetate/cyclohexanone compositions, and benzyl alcohol, aromatichydrocarbon/(NMP) compositions, respectively, which rely on cellulosicthickeners that sag or drip pulling the paint and varnish remover awayfrom the paint surface so that direct contact is lost. The loss ofcontact destroys penetrability before drying out.

U.S. Pat. Nos. 5,098,591; 5,124,062; 5,167,853; and 5,298,184 refer topaint and varnish removers based on combinations of (NMP) and variouscitrus terpene solvents. These compositions also contain cellulosic typethickeners, as well as organoclay thickening agents to aid in sagresistance and to control flow. U.S. Pat. No. 5,035,829 utilizesprimarily (NMP), acids and aklylene glycol ethers, and relies oncellulosic thickeners, and is used to remove over spray from spraybooths. U.S. Pat. Nos. 5,049,300; 5,098,592, and 5,154,848, disclosecompositions containing (NMP) and or (BLO) gamma-butyrolactone, andethyl 3-ethoxyproprionate (EEP) using cellulosic type thickeners toprovide thickening and sag resistance.

Thus, there remains a need in the art to provide an effective paint andvarnish stripper which has better sag resistance, especially on verticalsurfaces, while maintaining stripping effectiveness, along with thelower toxicities, volatilities, and environmental benefits that areoutlined in various patents, while avoiding the use of methylenechloride, toluene, methyl ethyl ketone, acetone, methanol or otherhighly volatile and/or flammable components.

Most traditional strippers containing methylene chloride or othervolatile and flammable chemicals such as methanol, methyl ethyl ketones,acetone or toluene, and strip paint quickly, but will remove only 1 or 2layers per application.

In the color change formulations, the natural color of the componentsfades to off-white when the stripping action has substantially ceased.The addition of a coloring agent, such as a dye or a pigment, to thecompositions in the range of up to 2%, will intensify the color change(i.e. a medium green to off-white or a pale green) to signal better tothe applicator that removal should begin. In addition, with the adventof modern day safer stripper formulations, the resulting strippingactions tend to be much slower than paint and varnish removers based onmethylene chloride, and other volatile, flammable solvents orcombinations thereof, so that it is difficult to determine when thestriping action is finished.

Furthermore, it is well known in the art, that modern day paints, basedon latexes, because of their tendency to buckle, swell and blister causedifficulties in maintaining contact with the layers of paint to bestripped. The stripping agent is pulled away from the surface by thebuckled and blistered paint. Often this results in the paint stripperand loosened top layers of paint to drop from the sub-layer of paintproducing a loss of direct contact with the paint stripper. The loss ofdirect contact requires additional application of paint stripper. Thus,there remains a need in the art to provide an effective paint andvarnish remover which has better sag resistance, very low odor, asignaling device to indicate the completion of paint stripper action,and an effective way to prevent the excessive bubbling, blistering andswelling that can lead to the types of problems described herein.

Furthermore, despite the present of surfactants and other wettingagents, soaps and the like, it has been proven through experimentationthat many of the compositions and formulas fail to loosen the paintlayers sufficiently if dried to the point where little or no liquid ispresent. Therefore, there remains a need in the art for a paint andvarnish remover that is removable at any stage wet or dry, even when theremover has totally dried.

It is advantageous if these improvements in the state of the art alsohas lower volatilities and, environmental benefits that are outlined invarious other patents referenced, while avoiding the use of methylenechloride, toluene, methyl ethyl ketone, acetone, methanol, ethanol orother highly volatile and/or flammable components.

The color change feature of the present invention signals the completionof the paint stripper action and indicates the time at which the paintstripper is ready to be removed along with the softened paint layers.The paint and varnish stripper of the present invention isbiodegradable, non-flammable, odor free and easily cleaned up withwater. It contains no methylene chloride or caustic. It truly clings tovertical surfaces. It removes most varieties of paints and varnishes,which are oil or water-based including latexes, stains, alkyds, andpolyurethane. It can be applied on a multitude of interior and exteriorsurfaces including wood, brick, plaster, metal, marble, masonry,concrete and fiberglass. It also strips significantly more paint thantraditional paint strippers.

SUMMARY OF THE INVENTION

In one embodiment, the present invention relates to a paint removalformulation having a color change feature to indicate when the strippingaction of the formulation has ceased and is ready for removal; theformulation comprises: at least one penetrant, at least one carrier andat least one colorant whereby the formulation is applied to the targetarea and there is a color change to indicate that the stripping actionof the formulation has ceased and is ready for the removal step.

In another embodiment, the penetrant is selected from a group consistingof NMP, benzyl alcohol, ethyl lactate, dimethyl adipate, dimethylglutarate, diethyl adipate, diethyl glutarate, ethyl benzoate, dimethylsuccinate, diethyl succinate, dimethyl phthalate, diethyl phthalate,dimethyl terphthalate, diethyl terphthalate, ethylene bis(lactate),dimethyl sulfoxide, soy solvents, D-limonene and mixtures thereof.

In still another embodiment, the carrier is selected from a groupconsisting of polysaccharides, starch, cellulose, polydextran, chitosan,chitin, limestone, metal oxides, aluminum silicates, hydratedaluminates, sodium magnesium silicates, barium sulphates, ferroxides,magnesium aluminum silicates and mixtures thereof. In yet anotherembodiment, the colorant is selected from a group consisting of dye,pigments and mixtures thereof. In a further embodiment, the penetrant isselected from a group consisting of methylene chloride, toluene, methylethyl ketone, acetone, methanol, xylenes, mineral spirits, hi-flashnaptha and mixtures thereof. In still yet another embodiment, theformulation further comprises water.

In still yet another embodiment, the colorant migrates away from asurface of the formulation as the surface of the formulation dries. Inanother embodiment, the carrier partially dehydrates and emits whitelight as the surface of the formulation dries.

In a further embodiment, the formulation comprises from about 5 to about55% by weight of the penetrant, from about 2 to about 50% by weight ofthe carrier, from about 0.01 to about 2.0% by weight of the colorant andfrom about 15 to about 50% by weight of the water.

In another embodiment, the formulation further comprises at least onethickening agents, said thickening agents being selected from a groupconsisting of Fullers earth, clay, attapulgite, montmorillonite,magnasol, klucel H, hydroxyethyl cellulose, hydroxypropyl cellulose,methocel and mixtures thereof. In still another embodiment, theformulation further comprises at least one wetting agent, said wettingagent being selected from a group consisting of propylene glycol,butylene glycol, ethylene glycol, diethylene glycol, triethylene glycol,tetraethylene glycol, pentaethylene glycol, neopentyl glycol, diethyleneglycol monomethyl ether, monomethyl ethers of triethylene glycol,tetraethylene glycol, pentaerythritol, dipentaerythiritol, neopentylglycol and mixtures thereof.

In yet another embodiment, the formulation further comprises at leastone activator, the activator being selected from a group consisting offormic acid, acetic acid, glycolic acid, hydroxyacetic acid,chloroacetic acid, fluoroacetic acid, oxalic acid, lactic acid andmixtures thereof.

In still yet another embodiment, the present invention provides for acolored paint removal product that becomes a paler color of the productafter it has been applied to the target area, has softened the paint andis ready for removal. In a further embodiment, the product comprises: atleast one penetrant, at least one carrier, and at least one colorantwhereby the product, when applied to the target area, changes color asthe surface of product dries, the carrier partially dehydrates emittingwhite light and the colorant migrates away from the dehydrating surface.In one embodiment, the colored product becomes white to indicate thatthe stripping action of the product has ceased and is ready for scrapingor removal step. More particularly, the product changes color by awhitening process whereby the colorant migrates away from thedehydrating surface leaving the finely divided carrier to emit whitelight. In another embodiment, the colored product becomes paler than itsoriginal color to indicate that the stripping action of the product hasceased and is ready for the removal step.

In another embodiment, the method of manufacturing a paint removalcomposition that changes color to indicate that the stripping action ofthe composition has substantially ceased and is ready for the scrapingor removal step, comprises admixing at least one penetrant, at least onecarrier, and at least one colorant whereby the composition is applied tothe target area and as the surface of the composition dries, the carrierpartially dehydrates emitting white light as the colorant migrates awayfrom the dehydrating surface. Hence, there is a color change to indicatethat the stripping action of the product has substantially ceased andpaint or varnish is ready for removal. For purposes of this inventionand this embodiment, the term substantially can mean from about 50 toabout 95% of the stripping action of the composition has occurred andthe user may begin scraping and removing the paint layers from themedium. For purposes of this invention, the terms “scraping” and“removal” may mean the same thing. In another embodiment, the term“scraping” may mean the back and forth motion by the user utilizing astripping or scraping tool. In a further embodiment, the term “removal”may mean the overall process of removing the paint with the paintremoval composition.

In still another embodiment, the method further comprises admixingwater. In yet another embodiment, the formulation comprises from about 5to about 50% by weight of the penetrant, from about 2 to about 50% byweight of the carrier, from about 0.01 to about 2.0% by weight of thecolorant and from about 15 to about 50% by weight of the water.

In still yet another embodiment, the method further comprises admixingat least one thickening agents, the thickening agents being selectedfrom a group consisting of Fullers earth, clay, attapulgite,montmorillonite, magnasol, klucel H, hydroxyethyl cellulose,hydroxypropyl cellulose, methocel and mixtures thereof.

In another embodiment, the method further comprises admixing at leastone wetting agent, the wetting agent being selected from a groupconsisting of propylene glycol, butylene glycol, ethylene glycol,neopentyl glycol, diethylene glycol, triethylene glycol, tetraethyleneglycol, pentaethylene glycol, diethylene glycol monomethyl ether,monomethyl ethers of triethylene glycol, tetraethylene glycol,pentaerythritol, dipentaerythritol, neopentyl glycol and mixturesthereof.

In yet another embodiment, the method further comprises admixing atleast one activator, the activator being selected from a groupconsisting of formic acid, acetic acid, glycolic acid, hydroxyaceticacid, chloroacetic acid, fluoroacetic acid, oxalic acid, lactic acid andmixtures thereof.

In still another embodiment, the method of manufacturing a paint removalcomposition that changes color to indicate that a stripping action ofthe composition has substantially ceased and is ready for a scrapingstep, the method comprises admixing at least one penetrant, at least onecarrier, and at least one colorant whereby the composition is applied tothe target area and there is a color change to indicate that thestripping action of the composition has substantially ceased and isready for scraping and removal, the penetrant is selected from a groupconsisting of NMP, benzyl alcohol, ethyl lactate, diethyl adipate,diethyl glutarate, ethyl benzoate, dimethyl succinate, diethylsuccinate, dimethyl phthalate, diethyl phthalate, dimethyl terphthalate,diethyl terphthalate, ethylene bis(lactate), dimethyl sulfoxide, soysolvents, D-limonene and mixtures thereof, and the carrier is selectedfrom a group consisting of polysaccharides, starch, cellulose,polydextran, chitosan, chitin, limestone, metal oxides, aluminumsilicates, hydrated aluminates, sodium magnesium silicates, bariumsulphates, ferroxides, magnesium aluminum silicates and mixturesthereof.

In a further embodiment, the penetrant and/or carrier of the formulationof the present invention has an inherent color and the color from thepenetrant and/or carrier is instrumental in the color change. In still afurther embodiment, the formulation comprises another component, not acolorant, that has an inherent color and the color from this componentis instrumental in the color change. In another further embodiment, acolor changing paint and varnish removal product is provided and theproduct comprises at least one penetrant and at least one carrier, andthe color of the product derived from the color of the penetrant changeswhen the stripping action of the product has substantially ceased andthe paint or varnish is ready for removal. In another embodiment, thepenetrant is the colorant.

In still a further embodiment, the carrier of the present invention andthe composition's viscosity may add additional benefits and resultsincluding but not limited to safe short-term human skin contact with theproduct or composition. In yet a further embodiment, the carrier mayalso function to mask the odor of other ingredients in the formulationthereby allowing for an odor free or odorless composition. In still yeta further embodiment, the present invention provides for better sagresistance and an effective way to prevent the excessive bubbling,blistering and swelling associated with problems relating to modem daypaints, in particular, latex paints.

In another embodiment, the present invention relates to a paint removalformulation having a color change feature to indicate when theformulation is ready for removal, the formulation comprises: at leastone penetrant, at least one water insoluble carrier and at least onecolor visible colorant whereby the formulation is applied to the targetarea and there is a color change to indicate when the stripping actionof said formulation has ceased and is ready for removal, said penetrantis selected from a group consisting of dimethyl adipate, dimethylglutarate, dimethyl succinate, butyl alcohol, ethyl alcohol, isopropylalcohol, tertiary butyl alcohol, methyl alcohol, di-iso butyl ketone,methyl amyl ketone, butyl acetate, tertiary butyl acetate, isobutyliso-butyrate, diethyl ether, ethylene glycol methyl ether, ethyleneglycol butyl ether, turpentine, aromatic hydrocarbon, cyclohexanone,isophrone, heptane, hexane, kerosene, lacquer diluents, rubber solvent,benzene, chlorobenzene, cyclohexanol, monoethanolamine and mixturesthereof, and said water insoluble carrier is selected from a groupconsisting of polysaccharides, starch, cellulose, polydextran, chitosan,chitin, limestone, metal oxides, aluminum silicates, hydratedaluminates, sodium magnesium silicates, barium sulphates, ferroxides,magnesium aluminum silicates and mixtures thereof, and said colorant isselected from a group consisting of dye, pigments and mixtures thereof.

In a further embodiment, the formulation has a viscosity from about 1200cps to about 4500 cps. In another further embodiment, the formulation isa semi-solid. In still another further embodiment, the colored paintremoval product that becomes a paler color of the product after theproduct is applied to the target area, has softened the paint and isready for removal, the product comprises: at least one penetrant, atleast one water insoluble carrier, and at least one color visiblecolorant whereby the product is applied to the target area and as thesurface of the product dries, the carrier partially dehydrates emittingwhite light as the colorant migrates away from the dehydrating surfaceand the product becomes paler than its original color to indicate thatthe stripping action of the product has ceased and is ready for theremoval step, the product having a viscosity from about 1200 cps toabout 4500 cps.

In yet a further embodiment, the method of manufacturing a paint removalcomposition that changes color to indicate that a stripping action ofsaid composition has substantially ceased and is ready for a scrapingstep, said method comprising admixing at least one penetrant, at leastone water insoluble carrier, and at least one color visible colorantwhereby the composition is applied to the target area and there is acolor change to indicate that the stripping action of the compositionhas substantially ceased and is ready for scraping and removal, thepenetrant is selected from a group consisting of NMP, benzyl alcohol,ethyl lactate, diethyl adipate, diethyl glutarate, ethyl benzoate,dimethyl succinate, diethyl succinate, dimethyl phthalate, diethylphthalate, dimethyl terphthalate, diethyl terphthalate, ethylenebis(lactate), dimethyl sulfoxide, soy solvents, D-limonene, methylenechloride, toluene, methyl ethyl ketone, acetone, methanol, xylenes,mineral spirits, hi-flash naptha, dimethyl adipate, dimethyl glutarate,dimethyl succinate, butyl alcohol, ethyl alcohol, isopropyl alcohol,tertiary butyl alcohol, methyl alcohol, di-iso butyl ketone, methyl amylketone, butyl acetate, tertiary butyl acetate, isobutyl iso-butyrate,diethyl ether, ethylene glycol methyl ether, ethylene glycol butylether, turpentine, aromatic hydrocarbon, cyclohexanone, isophrone,heptane, hexane, kerosene, lacquer diluents, rubber solvent, benzene,chlorobenzene, cyclohexanol, monoethanolamine and mixtures thereof, andthe carrier is selected from a group consisting of polysaccharides,starch, cellulose, polydextran, chitosan, chitin, limestone, metaloxides, aluminum silicates, hydrated aluminates, sodium magnesiumsilicates, barium sulphates, ferroxides, magnesium aluminum silicatesand mixtures thereof, and the composition having a viscosity from about1200 cps to about 4500 cps.

In another embodiment, as the product or formulation dries, watervaporizes from the surfaces and the residual liquid penetrant migratesfrom the surface toward the stripper-paint interface carrying along thecolor pigment. These two concurrent or simultaneous actions produce asurface crust of tiny gelatinous beads in the particle size regime of200 to 2000 nanometers as the topography. These particles scatter thevisible light (Mie Scattering) into white light and produce thewhitening and dilution of the visible color.

In a further embodiment, the drying of the formulation and the migrationof the penetrant produces a surface crust of beads, the beads having aparticle size that scatter visible light into white light and producesthe whitening and dilution of the visible color. In another furtherembodiment, the particle of the beads is from about 200 to about 2,000nanometers. In yet another further embodiment, the carrier partiallydehydrates emitting white light as the surface of the formulation dries.

In still another embodiment, the penetrant and/or carrier is eithercolorless, white or opaque and the colorant has a distinctive color;thus, when the colorant migrates away from the surface of the product,the visible color on the surface of the product will be a faded orlighter color of the colorant. For example, a green colorant and awhite, colorless or opaque penetrant and/or carrier will cause theproduct to change from a green to light green when the stripping actionhas ceased and is ready for removal. In still a further embodiment, thethe penetrant and/or carrier has a different color from the color of thecolorant; thus, when the colorant migrates away from the surface of theformulation, the visible color on the surface of the formulation will beinfluenced by the color of the penetrant and/or carrier. For example, ablue colorant and a green pentrant and/or carrier will cause the productto change from blue to green when the stripping action has ceased and isready for removal.

In still yet another embodiment, the formulation and products of thepresent invention uses hydroxypropyl cellulose (“Methocel”) as athickener and the penetrant is NMP; NMP has a low density and by usingMethocel, there are no pH problems, no problems with dealing with thelow density of NMP; and the formulation is stable and does not separate.In a further embodiment, the Methocel is added in the early stages ofmanufacturing to form the gel of the formulation and Methocel gel isresponsible for keeping all of the raw material together and preventsthem from separating out. In another further embodiment, the acrylicpolymer emulsion acts as a binder and further prevents the ingredientsin the formulation from separating.

DETAILED DESCRIPTION OF THE INVENTION

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention that may be embodied in variousforms. Therefore, specific functional details disclosed herein are notto be interpreted as limiting, but merely as a basis for the claims andas a representative basis for teaching one skilled in the art to employthe present invention in various ways.

The specific examples below will enable the invention to be betterunderstood. However, they are given merely by way of guidance and do notimply any limitation.

EXAMPLE 1

One embodiment of the paint and varnish remover of the present inventionmarketed under the trademark “READY STRIP® PLUS” was tested to determineif it would indicate a color change when the remover was finishedworking and was ready for the stripping step. In addition, the strippingsteps were conducted at different time intervals to evaluate further thenumber of layers of paint removed at such time intervals. The timeintervals included times prior to color change, at color change andafter color change.

Test Sample

A pine plank measuring 9 3/16 inches wide by 72 3/16 inches long by0.748 (¾) inch thick painted with twelve (12) coats of paint of varyingcolors was the test sample. Each paint coat was visible from one end ofthe plank by successive receding starting points of four (4) inchspacing for each paint coat. Prior to applying the first paint coat, thepine plank had been sealed with a varnish sanding sealer and sanded withsandpaper.

Paint Materials

The paints used were as follows in the identified sequence ofapplication: 1.) Black latex flat enamel; 2.) White hi-gloss,interior/exterior alkyd spray enamel; 3.) Wildflower Blue latex satinenamel; 4.) Claret Wine latex satin enamel; 5.) Taupe latex satinenamel; 6.) Hunter Green interior/exterior alkyd spray enamel; 7.)Cinnamon latex satin enamel; 8.) White hi-gloss latex enamel; 9.) BannerRed hi-gloss, interior/exterior alkyd spray enamel; 10.) Black latexflat enamel; 11.) Yellow hi-gloss, interior/exterior alkyd spray enamel;and 12.) Wildflower Blue latex satin enamel.

Instruments

The average film thickness per paint coat was ascertained by measuringthe pine plank with a vernier micrometer following the sanding step andfollowing the dried twelve (12) coats of paint. The paint scrapers usedwere a triangular drag scraper with a stainless steel blade measuring6.2 cm (2.44 inches) per edge and a “five-in-one” flat blade paintscraper with a stainless steel blade measuring 5.8 cm (2.283 inches).The applicators for applying the paint strippers were two-inch widepaint brushes.

Paint Application Procedure

The pine board (plank) was first coated with a varnish sanding sealerand allowed to dry overnight [about sixteen (16) hours]. The board wassanded with 220 grain sandpaper to provide a smooth sealed wood surface.The paint coatings were applied with successive receding starting pointsat four (4) inch spacings so that each paint coat remained visible andtraceable. The order of the paint coat deposition was black, white,blue, claret wine, taupe, hunter green, cinnamon, white, banner red,black, yellow, and blue. After the application of each paint coat, thepaint was allowed to dry for four (4) hours. The first two (2) hours ofdrying was at ambient temperature which varied from 81° F. to 92° F.during the ambient drying step for the twelve (12) paint coats. The lasttwo (2) hours, the drying was carried out under a hot air stream thatvaried in temperature between 105° F. to 122° F. After the third, thesixth, and the ninth paint coats, the entire drying was at ambienttemperature overnight (14-16 hours). The overnight temperatures variedbetween 78° F. to 90° F. Following the final paint coat, the paintedplank was left to cure for one hundred seventeen (117) hours underconditions of controlled temperature and humidity. The controlled curingenvironment was a temperature of 70° F. and humidity of 40-45%.

The dry film thickness of the twelve coats (12) of paint measured, withthe vernier micrometer, 0.5 mm or 19.685 mil. The average dry paint coatthickness calculates to be 1.64 mil.

Ready Strip Application Procedure:

The READY STRIP® PLUS was applied to the top paint coat (blue) coveringthe eleven (11) paint coats beneath it. Both paint strippers wereapplied to cover a rectangular section of the painted plank thatmeasured approximately 9½ inches by 3¼ inches with a thicknesssufficient to mask the top paint color (blue). As initially applied, theREADY STRIP PLUS had a medium green color. The Plus paint stripperturned color as the active ingredients penetrated the twelve (12) paintcoats. The READY STRIP® PLUS changed color from medium green to a palegreen after twenty-four (24) hours.

The test results of Example 1 are set forth in Table 1 below: TABLE 1Elapsed Paint Time, Coats Stripper Time Hours Removed READY STRIP ® PLUS5¹⁵ pm 4  4 (Aug. 09, 2005) READY STRIP ® PLUS 9¹⁵ pm 8  7 (Aug. 09,2005) READY STRIP ® PLUS 1¹⁵ pm 24 12 (Aug. 10, 2005) READY STRIP ® PLUS1¹⁵ pm 72  12^(b) (Aug. 12, 2005)^(b)The READY STRIP ® PLUS had dried to a hard layer. Water was layeredover the dried paint stripper and allowed to soak into the stripper forabout ten (10) minutes. The hydrated paint stripper was able to bepenetrated with the drag scraper and twelve paint coats came off easily.

The stripping action was tested prior to full color change (partialcolor change) at the 4^(th) and 8^(th) hour of testing and only four (4)and seven (7) layers of paint, respectively were removed. The full colorchange (medium green to pale green) occurred at the 24^(th) hour and alltwelve (12) layers of paint were removed. In addition, the ₇₂ ^(nd) hourwas also tested and the color remained changed, and all twelve (12)layers were removed.

EXAMPLE 2

Another embodiment of the paint and varnish remover of the presentinvention marketed under the trademark “READY STRIP® PRO” was tested todetermine if it would indicate a color change when the remover wasfinished working and was ready for the stripping step. Again, thestripping steps were conducted at different time intervals to furtherevaluate the number of layers of paint removed at such time intervals.The time intervals included times prior to color change, at color changeand after color change.

Test Sample:

A pine plank measuring 9 3/16 inches wide by 72 3/16 inches long by0.748 ( 3/4) inch thick painted with twelve (12) coats of paint ofvarying colors was the test sample. Each paint coat was visible from oneend of the plank by successive receding starting points of four (4) inchspacing for each paint coat. Prior to applying the first paint coat, thepine plank had been sealed with a varnish sanding sealer and sanded withsandpaper.

Paint Materials:

The paints used were as follows in the identified sequence ofapplication: 1.) Black latex flat enamel; 2.) White hi-gloss,interior/exterior alkyd spray enamel; 3.) Wildflower Blue latex satinenamel; 4.) Claret Wine latex satin enamel; 5.) Taupe latex satinenamel; 6.) Hunter Green interior/exterior alkyd spray enamel; 7.)Cinnamon latex satin enamel; 8.) White hi-gloss latex enamel; 9.) BannerRed hi-gloss, interior/exterior alkyd spray enamel; 10.) Black latexflat enamel; 11.) Yellow hi-gloss, interior/exterior alkyd spray enamel;and 12.) Wildflower Blue latex satin enamel.

Instruments:

The average film thickness per paint coat was ascertained by measuringthe pine plank with a vernier micrometer following the sanding step andfollowing the dried twelve (12) coats of paint. The paint scrapers usedwere a triangular drag scraper with a stainless steel blade measuring6.2 cm (2.44 inches) per edge and a “five-in-one” flat blade paintscraper with a stainless steel blade measuring 5.8 cm (2.283 inches).The applicators for applying the paint strippers were two-inch widepaint brushes.

Paint Application Procedure:

The pine board (plank) was first coated with a varnish sanding sealerand allowed to dry overnight [about sixteen (16) hours]. The board wassanded with 220 grain sandpaper to provide a smooth sealed wood surface.The paint coatings were applied with successive receding starting pointsat four (4) inch spacings so that each paint coat remained visible andtraceable. The order of the paint coat deposition was black, white,blue, claret wine, taupe, hunter green, cinnamon, white, banner red,black, yellow, and blue. After the application of each paint coat, thepaint was allowed to dry for four (4) hours. The first two (2) hours ofdrying was at ambient temperature which varied from 81° F. to 92° F.during the ambient drying step for the twelve (12) paint coats. The lasttwo (2) hours, the drying was carried out under a hot air stream thatvaried in temperature between 105° F. to 122° F. After the third, thesixth, and the ninth paint coats, the entire drying was at ambienttemperature overnight (14-16 hours). The overnight temperatures variedbetween 78° F. to 90° F. Following the final paint coat, the paintedplank was left to cure for one hundred seventeen (117) hours underconditions of controlled temperature and humidity. The controlled curingenvironment was a temperature of 70° F. and humidity of 40-45%.

The dry film thickness of the twelve coats (12) of paint measured, withthe vernier micrometer, 0.5 mm or 19.685 mil. The average dry paint coatthickness calculates to be 1.64 mil.

Ready Strip Application Procedure:

The READY STRIP® PRO was applied to the top paint coat (blue) coveringthe eleven (11) paint coats beneath it. The Pro paint stripper wasapplied to cover a rectangular section of the painted plank thatmeasured approximately 9½ inches by 3¼ inches with a thicknesssufficient to mask the top paint color (blue). As initially applied, theREADY STRIP® PRO had a medium brown color. The Pro paint strippersturned color as the active ingredients penetrated the twelve (12) paintcoats. The READY STRIP® PRO substantially turned color from a mediumbrown to a very light tan at the eight (8) hour mark and fully turnedcolor from medium brown to off-white after twenty-four (24) hours.

The test results of Example 2 are set forth in Table 2 below: TABLE 2Elapsed Paint Time, Coats Stripper Time Hours Removed READY STRIP ® PRO5¹⁵ pm 4  4 (Aug. 09, 2005) READY STRIP ® PRO 9¹⁵ pm 8 12 (Aug. 09,2005) READY STRIP ® PRO 1¹⁵ pm 24 12 (Aug. 10, 2005) READY STRIP ® PRO1¹⁵ pm 72  12^(a) (Aug. 12, 2005)^(a)The READY STRIP ® PRO had crusted over but was sufficiently pliableso that the drag scraper was able to cut through the crust and removethe twelve (12) paint coats.

The stripping action was tested prior to full color change (partialcolor change) at the 4^(th) hour of testing and four (4) layers of paintwere removed. A substantial color change (brown to light tan) occurredat the 8^(th) hour of testing and all twelve (12) layers of paint wereremoved. The full color change (brown to off-white) occurred at the24^(th) hour and all twelve (12) layers of paint were removed. Inaddition, the ₇₂ ^(nd) hour was also tested and the color remainedchanged, and all twelve (12) layers were removed.

EXAMPLE 3

The formulation and product of the present invention was also tested forsafety for human skin contact. The Ready Strip® Product is a gelatinoussemi-solid and not a free flowing liquid such as an aqueous solution ofNMP in water. This test compares the Ready Strip Product with a 10-15%aqueous solution of NMP. The molecular movement of NMP from thecontracting agent onto the skin of the hand is governed by Fick'smolecular transport equation, which is stated below.J=−(RT/f)(dc/dx)=−D(dc/dx)  A)Where:

J=flux density in moles cm⁻²s⁻¹

R=gas constant=8.31451×10⁷ dynes cm K⁻¹mol⁻¹

T=temperature in degrees Kelvin

f=friction coefficient

D=diffusion coefficient in cm⁻²s⁻¹

dc/dx=concentration gradient or the entropic driving force for molecularmovement from higher concentration to lower

Where, f, the friction coefficient is

f=3πηd

η=viscosity in poise or dynes cm⁻² (g cm⁻¹s⁻¹)

d=diameter of hydrated NMP molecule (NMP 3H₂0)=4.73×10⁻⁸ cm calculatedvia Φ_(d)=0.2457 (MW)^(0.588); Φ_(d)0.2457 (153.1793)^(0.588)

So that, f=(44.6246×10⁻⁶ cm)(η), and the molecular flux equationbecomes:J=−(RT/3πηd)(dc/dx)  B)Isolating the independent impact of viscosity.J=−(1/η)(RT/3πd)(dc/dx)  C)And quantifying RT/3πd, the molecular flux equation becomesJ=−(1/η)(5.56×10¹⁶ dynes mol⁻¹ dc/dx)  D)

As equation D portrays, the molecular transport from the NMP containingagent to the hand is totally controlled by the concentration gradient(dc/dx) and the viscosity (η). Since the concentration gradient is notbeing varied, the only independent component controlling the flux is theviscosity. The relationship of the viscosity to the molecular transportof the NMP to the hand from the NMP containing agent is a recipricalone. As the viscosity increases, the transport flux of NMP decreasesproportionally.

The viscosity of a 10-15% aqueous solution of NMP is reported to be at3.3-4.0 centipoise (cp) at 25° C.

The measured viscosity of the Ready Strip® Product is 4,064 cp at 25° C.

The ratio of the viscosity of the Ready Strip® Product to the viscosityof a 10-15% NMP water solution is 1,016. Consequently, the moleculartransport to the hand of NMP from the water solution is 1,016 timesfaster than the corresponding transport of NMP from the Ready Strip®Product. At the same concentration, NMP will be absorbed by a hand incontact with the Ready Strip® Product at a rate factor of the ratio ofthe viscosities as calculated below: $\begin{matrix}{{{Rate}\quad{Factor}} = \begin{bmatrix}{{viscosity}\quad{of}\quad{the}\quad{NMP}\quad{aqueous}\quad{{solution}/}} \\{{viscosity}\quad{of}\quad{the}\quad{Ready}\quad{{Strip}®}}\end{bmatrix}} \\{= \left\lbrack {4\quad{cp}\text{/}4\text{,}064\quad{cp}} \right\rbrack} \\{= {9.8 \times 10^{- 4}}}\end{matrix}$Consequently, the rate of absorption from the Ready Strip® Product is9.8×10⁻⁴ times the rate of absorption of NMP onto a hand immersed in anaqueous solution of NMP.

With the NMP flux density of 30 μg cm⁻²hr⁻¹ for a 10-15% NMP aqueoussolution, a hand in such a solution for one hour would transfer 12,600μg of NMP from the aqueous solution to one hand.

For one hand in one hour: J=(30 μg cm⁻²hr⁻¹)(420 cm²)=12,600 μg/hr

For two hands in one hour: J=12,600 μg/hr for one hand×2=25,200 μg/hr

Whereas, a hand in the Ready Stripe® Product for one hour would transferto one hand 12.4 μg.

For one hand in one hour: J=(30 μg cm⁻²hr⁻¹)(420 cm²)/1016=12.4 μg/hr

For two hands in one hour: J=12.4 μg/hr for one hand×2=24.8 μg/hr

Proposition 65 provides for a dermal maximum allowable dose level (MADL)of 17,000 μg NMP/day. Testing has shown that the total absorbed dose ofNMP from the Ready Strip® Product, whether it is one or two hands, isfar below the Proposition 65 MADL.

Assuming a more reasonable contact time of five (5) minutes, the aqueoussolution will transfer 1,050 μg of NMP in 5 minutes, whereas the ReadyStrip® Product would transfer 1.03 μg of NMP in 5 minutes.

In conclusion, and as a consequence of the gelatinous, semi-solid natureof the Ready Strip® Product, its high viscosity and its slow rate ofabsorption, dipping one's hand into the Ready Strip® Product transfersexceeding small quantities of NMP to the body through the hands,quantities well below the maximum allowable dose level (MADL) of 17,000μg NMP/day. NMP is not considered a toxic molecule and shows no humanskin irritation over a twenty-four (24) hour exposure. Thus, the ReadyStrip® Product is safe for short-term contact with human skin.

EXAMPLE 4

The product and formulation of the present invention was also clinicallytested for safety to short term human skin contact. The studies includedthe evaluation of the dermal tolerance of the product on twenty-six (26)subjects (both male and female ranging in ages 19 to 65 years) followinga brief exaggerated application regimen. The regimen is as follows: theProduct was applied to two test sites on each subject (left and rightforearms); the Product was allowed to remain on both arms for one (1)hour; the first arm was rinsed with warm tap water for approximately 30seconds; the second arm was wiped off using a soft disposable cloth andtwo (2) hours after application, the wiped arm was rinsed with warmwater for approximately 30 seconds. Dermal irritation and sensation weremeasured at the one (1) hour point after washing and wiping of therespective arms and two (2) hours after the washing of the second arm.Twenty-four (24) and forty-eight (48) hours after removal, the subjectsreturned to the lab and the dermal assessments were repeated.

The test results showed no clinically significant reactions wereobserved. After two (2) hours, all twenty-six (26) subjects showed noskin irritation or sensation to the Product. After twenty-four (24)hours and forty-eight (48) hours, twenty-five out of the twenty-sixsubjects showed no skin irritation and sensation to the Product [the labconcluded that the twenty-sixth subject (subject number 11) had pimpleswhich were caused by an outside factor (shaving)].

Based on the Clinical Studies, the testing facility has concluded thatthe following claims can be made for the Ready Strip® Product:“Clinically shown to be safe for human skin contact”; “Safety tested forhuman skin contact”; “Dermatologically tested”; “So safe . . . you canput your hands in it”; and “Independent laboratory testing has shownReady Strip® to be safe for human skin contact”.

Therefore, while the embodiments of the present invention disclosedherein are presently considered to be preferred, various changes andmodifications can be made without departing from the spirit and scope ofthe invention. The scope of the invention is indicated in the appendedclaims, and all changes that come within the meaning and range ofequivalents are intended to be embraced therein.

1. A paint removal formulation having a color change feature to indicatewhen the formulation is ready for removal, said formulation comprising:at least one penetrant, at least one water insoluble carrier and atleast one color visible colorant, said penetrant is selected from agroup consisting of dimethyl adipate, dimethyl glutarate, dimethylsuccinate, butyl alcohol, ethyl alcohol, isopropyl alcohol, tertiarybutyl alcohol, methyl alcohol, di-iso butyl ketone, methyl amyl ketone,butyl acetate, tertiary butyl acetate, isobutyl iso-butyrate, diethylether, ethylene glycol methyl ether, ethylene glycol butyl ether,turpentine distilled steam, aromatic hydrocarbon, cyclohexanone,isophrone, heptane, hexane, kerosene, lacquer diluents, rubber solvent,benzene, chlorobenzene, cyclohexanol, monoethanolamine and mixturesthereof, and said water insoluble carrier is selected from a groupconsisting of polysaccharides, starch, cellulose, polydextran, chitosan,chitin, limestone, metal oxides, aluminum silicates, hydratedaluminates, sodium magnesium silicates, barium sulphates, ferroxides,magnesium aluminum silicates and mixtures thereof; and whereby saidformulation is designed to be applied to a target area and as thesurface of said formulation dries, said penetrant migrates away from asurface of said formulation carrying the visible color and therebycreating a color change to indicate that said formulation with thestripped paint is ready for removal.
 2. The formulation of claim 1wherein the drying of the formulation and the migration of the penetrantproduces a surface crust of beads, said beads having a particle sizethat scatter visible light into white light and produces the whiteningand dilution of the visible color.
 3. The formulation of claim 2 whereinsaid carrier partially dehydrates emitting white light as the surface ofsaid formulation dries.
 4. The formulation of claim 2 wherein theparticle of said beads is from about 200 to about 2,000 namometers. 5.The formulation of claim 4 wherein said formulation comprises from about5 to about 55% by weight of said penetrant, from about 2 to about 50% byweight of said carrier, from about 0.01 to about 2.0% by weight of saidcolorant and from about 15 to about 50% by weight of said water.
 6. Theformulation of claim 1 further comprises at least one thickening agent,said thickening agent being selected from a group consisting of Fullersearth, clay, attapulgite, montmorillonite, magnasol, klucel H,hydroxyethyl cellulose, hydroxypropyl cellulose, methocel and mixturesthereof.
 7. The formulation of claim 1 further comprises at least onewetting agent, said wetting agent being selected from a group consistingof propylene glycol, butylene glycol, ethylene glycol, diethyleneglycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol,diethylene glycol monomethyl ether, monomethyl ethers of triethyleneglycol, tetraethylene glycol, pentaerythritol, dipentaerythritol,neopentyl glycol and mixtures thereof.
 8. The formulation of claim 1further comprises at least one activator, said activator being selectedfrom a group consisting of formic acid, acetic acid, glycolic acid,hydroxyacetic acid, chloroacetic acid, fluoroacetic acid, oxalic acid,lactic acid and mixtures thereof.
 9. The formulation of claim 1 whereinsaid formaulation has a viscosity from about 1200 cps to about 4500 cps.10. The formulation of claim 1 wherein said formulation is a semi-solid.11. A colored paint removal product with a color changing feature, saidproduct comprises: at least one penetrant, at least one water insolublecarrier, and at least one color visible colorant whereby the product isapplied to the target area and as the surface of product dries, saidcarrier partially dehydrates emitting white light as said colorantmigrates away from the dehydrating surface and the product becomes palerthan its original color to indicate that the stripping action of saidproduct has ceased and is ready for the removal step, said producthaving a viscosity from about 1200 cps to about 4500 cps; and wherebythe product is designed to be applied to the target area and as thesurface of product dries, said colorant migrates away from thedehydrating surface and the drying of the product and the migration ofthe penetrant forms a surface crust of beads, said beads having aparticle size from about 200 to about 2,000 nanometers, said particlesize allows for scattering of visible light into white light therebycausing the product to change color to indicate that said product withthe paint is ready for the removal step.
 12. The product of claim 11wherein said product is a semi-solid and said color change is based onthe product losing color.
 13. The product of claim 11 wherein saidpenetrant is selected from a group consisting of NMP, benzyl alcohol,ethyl lactate, diethyl adipate, diethyl glutarate, ethyl benzoate,dimethyl succinate, diethyl succinate, dimethyl phthalate, diethylphthalate, dimethyl terphthalate, diethyl terphthalate, ethylenebis(lactate), dimethyl sulfoxide, soy solvents, D-limonene, methylenechloride, toluene, methyl ethyl ketone, acetone, methanol, xylenes,mineral spirits, hi-flash naptha, dimethyl adipate, dimethyl glutarate,dimethyl succinate,butyl alcohol, ethyl alcohol, isopropyl alcohol,tertiary butyl alcohol, methyl alcohol, di-iso butyl ketone, methyl amylketone, butyl acetate, tertiary butyl acetate, isobutyl iso-butyrate,diethyl ether, ethylene glycol methyl ether, ethylene glycol butylether, turpentine, aromatic hydrocarbon, cyclohexanone, isophrone,heptane, hexane, kerosene, lacquer diluents, rubber solvent, benzene,chlorobenzene, cyclohexanol, monoethanolamine and mixtures thereof. 14.The product of claim 11 wherein said carrier is selected from a groupconsisting of polysaccharides, starch, cellulose, polydextran, chitosan,chitin, limestone, metal oxides, aluminum silicates, hydratedaluminates, sodium magnesium silicates, barium sulphates, ferroxides,magnesium aluminum silicates and mixtures thereof.
 15. The product ofclaim 11 wherein said colorant is selected from a group consisting ofdye, pigments and mixtures thereof.
 16. The product of claim 11 furthercomprises water.
 17. The product of claim 16 wherein said formulationcomprises from about 5 to about 55% by weight of said penetrant, fromabout 2 to about 50% by weight of said carrier, from about 0.01 to about2.0% by weight of said colorant and from about 15 to about 50% by weightof said water.
 18. The product of claim 11 further comprises at leastone thickening agent, said thickening agent being selected from a groupconsisting of Fullers earth, clay, attapulgite, montmorillonite,magnasol, klucel H, hydroxyethyl cellulose, hydroxypropyl cellulose,methocel and mixtures thereof, said product further comprises at leastone wetting agent, said wetting agent being selected from a groupconsisting of propylene glycol, butylene glycol, ethylene glycol,diethylene glycol, triethylene glycol, tetraethylene glycol,pentaethylene glycol, diethylene glycol monomethyl ether, monomethylethers of triethylene glycol, tetraethylene glycol, pentaerythritol,dipentaerythritol, neopentyl glycol and mixtures thereof, said product,further comprises at least one activator, said activator being selectedfrom a group consisting of formic acid, acetic acid, glycolic acid,hydroxyacetic acid, chloroacetic acid, fluoroacetic acid, oxalic acid,lactic acid and mixtures thereof.
 19. A method of manufacturing a paintremoval composition with a color change feature, said method comprisingadmixing at least one penetrant, at least one water insoluble carrier,and at least one color visible colorant, said penetrant is selected froma group consisting of NMP, benzyl alcohol, ethyl lactate, diethyladipate, diethyl glutarate, ethyl benzoate, dimethyl succinate, diethylsuccinate, dimethyl phthalate, diethyl phthalate, dimethyl terphthalate,diethyl terphthalate, ethylene bis(lactate), dimethyl sulfoxide, soysolvents, D-limonene, methylene chloride, toluene, methyl ethyl ketone,acetone, methanol, xylenes, mineral spirits, hi-flash naptha, dimethyladipate, dimethyl glutarate, dimethyl succinate, butyl alcohol, ethylalcohol, isopropyl alcohol, tertiary butyl alcohol, methyl alcohol,di-iso butyl ketone, methyl amyl ketone, butyl acetate, tertiary butylacetate, isobutyl iso-butyrate, diethyl ether, ethylene glycol methylether, ethylene glycol butyl ether, turpentine, aromatic hydrocarbon,cyclohexanone, isophrone, heptane, hexane, kerosene, lacquer diluents,rubber solvent, benzene, chlorobenzene, cyclohexanol, monoethanolamineand mixtures thereof, and said carrier is selected from a groupconsisting of polysaccharides, starch, cellulose, polydextran, chitosan,chitin, limestone, metal oxides, aluminum silicates, hydratedaluminates, sodium magnesium silicates, barium sulphates, ferroxides,magnesium aluminum silicates and mixtures thereof, said compositionhaving a viscosity from about 1200 cps to about 4500 cps; and wherebysaid composition is designed to be applied to a target area and saidcomposition changes color when said composition with the stripped paintis ready for scraping and removal.
 20. The method of claim 19 whereinsaid composition is a semi-solid, said composition being safe for shortterm human skin contact.